An effort to prosecute the self-proclaimed mastermind of the Sept. 11 terrorist attack and four co-defendants veered off track again Thursday as a pretrial hearing ended with new obstacles that threaten to further derail the case before a military tribunal at Guantanamo Bay.

At 8:32 am Wednesday morning, on the first day that the National September 11 Memorial Museum opened to the public, 26 uniformed police officers and firefighters marched onto the lawn of the memorial and unfurled an American flag that had flown at 90 West Street, adjacent to Ground Zero, for weeks after the attacks.

As the days following 9/11 turned into passing years, park rangers at the Flight 93 National Memorial began to face an unplanned challenge. Parents reliving the tragic day terrorists attacked the nation were approaching park staff, asking them to explain the sometimes dark, difficult subject matter in a way their young children would understand, park Superintendent Jeff Reinbold said. In most cases, the youngsters weren’t alive the day Flight 93 crashed, killing its 40 passengers, he said.

A pretrial hearing for suspects in the Sept. 11 terror attacks is in recess until mid-week while the military judge decides whether to reconsider his decision to try one of the men separate from the other four. Army Col. James Pohl heard arguments for about an hour Monday at the U.S. naval base in Guantanamo Bay, Cuba. More.